In [3]:
Image('../Plots/akari_conf_title.png')
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Outline:

Introduction:

  • What is anomalous microwave emission? (AME)
  • Why is AKARI useful?

Our approach:

  • Compare Planck AME map with IR maps
  • Can we say more than "AME Correlates with dust"

All-sky Results

$\lambda$ Orionis Results

Conclusions and future work

  • Can we rule out spinning PAHs?

Intro: What's in the microwave sky?

In [3]:
hp.mollview(lfi30ghz,
           title = 'Planck Low Frequency Instrument: 30 GHz All-sky map',
           norm = 'hist',
           cmap = 'rainbow',
           unit = '$K_{CMB}$')

alt text

From "Planck 2015 results. X. Diffuse component separation: Foreground maps":

https://arxiv.org/abs/1502.01588

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Image('../Plots/akari_conf_intro_spinning_dust.png')
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Image('../Plots/akari_conf_intro_hensley.png')
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Image('../Plots/akari_conf_intro_irc9.png')
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1. All-sky comparison

2. Localized inspection of $\lambda$ Orionis

Major caveats:

  • Limited to ~1-degree resolution
  • No "ground truth" AME map !!
  • Envrionmental variations not well constrained on an all-sky basis

Intro: Why AKARI?

  • #### Dominated by PAH emission features
  • #### IRC 9 $\mu{}m$ to IRAS 12 $\mu{}m$ ratio may reveal trends in PAH ionization
In [7]:
Image(filename = PATH + "/png/band-ratio-G100.png")
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  • $G_{0}$ indicates the interstellar radiation field relative to the solar neighborhood

All-sky results

Each IR band's intensity vs. AME Intensity:

In [23]:
Image('../Plots/png/AMEvsDust_allsky_allbands__mpsub_kde.png')
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What if scale by the radiation field strength ($U$)?

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Image('../Plots/png/AMEvsDust_allsky_allbands__mpsub__UNorm_kde.png')
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  • $U$ is approximated as the dust radiance $R$ divided by the optical depth $\tau_{353 GHz}$
  • $R$ and $\tau_{353 GHz}$ are from the Planck PR1 thermal dust parameter maps

Spearman Correlation Matrix:

IR Bands' Intensity and AME

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Image('../Plots/png/all_bands_corr_matrix_wAME_spearmanintensity.png')
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Spearman Correlations:

After normalizing data by ISRF ( ~ $\frac{R}{\tau_{353 GHz}}$)
In [12]:
Image('../Plots/png/all_bands_corr_matrix_wAME_spearmanU_norm.png')
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Almost no change when dividing by $U$

Spatial Variation of Correlation Strength

$I_{9}$ to $I_{AME}$ correlation strength for ~10 degree patches:

In [14]:
Image('../Plots/Allsky_Corr/Spearman_Map_nside8_A9toAME.png')
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  • ###### Looks like a Galaxy...
  • ###### Weaker correlation at higher latitudes

$I_{140}$ to $I_{AME}$ correlation strength for ~10 degree patches:

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Image('../Plots/Allsky_Corr/Spearman_Map_nside8_A140toAME.png')
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What if we normalize by the dust radiance?

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Image('../Plots/Allsky_Corr/RadNorm/Spearman_Map_nside8_A9toAME.png')
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  • Now the map flattens-out
  • Consistent with Hensley+ (2016)
  • ...but is this indicating lack of AME:PAH correlation?
  • Are we encountering too much noise/systematic effects in the maps?

$\lambda$ Orionis Results:

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Image('../Plots/png/LOri_akari9_AMEcont_1dres.png')
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  • The binary star $\lambda$ Orionis, is located near the center of the ring.
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Image('../Plots/lOrionis_grid_img.png')
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$\lambda$ Orionis Results:

Spearman Correlation Matrix

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Image('../Plots/png/Allsky_corr_Lori.png')
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18 micron to 65 micron bands correlate the worst? AME apparently weaker at higher $T_{dust}$ pixels Destruction of PAHs in the center? Something else? ..stay tuned for dust SED modeling (with help from F. Galliano)

$\lambda$ Orionis Results:

What about PAH ionization fraction?

In [21]:
Image('../Plots/png/Lori_A9I12.png')
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  • Stronger AME relates to higher 9 to 12 micron intensity ratio
  • Interesting because both bands are weak in the central region
  • PAH ionization fraction needs more attention...

Conclusions:

All-sky:

  • All-sky dust comparisons are a mess (see F. Boulanger's talk)
  • Present data do not rule out spinning-PAHs, however:
  • They also do not indicate exclusive PAH-AME relationship

$\lambda$ Orionis

  • PAH-tracing emission correlates as well with AME as FIR in $\lambda$ Orionis
  • Correlation of 9 to 12 $\mu{}m$ ratio suggests PAH ionization needs more consideration.
  • PRELIMINARY: SED fitting indicates that $S(I_{AME}:M_{PAH}$ may be stronger than $S(I_{AME}:M_{dust}$

Open questions:

  • What about noise and systematic affects?
    • Effect on correlation tests
  • If not PAHs, what about other spinning stuff? (nanosilicates, etc. see T. Hoang's talk)
    • "What about the magnetic dust?" - Magnetic dipole emission not dead yet?
  • Do we know enough about the dust in different environments? (F. Boulanger's talk again)
  • How well do the Planck Component maps really constrain AME?
  • How well do we understand the structure of $\lambda$ Orionis?

Future (Ongoing) Work:

  • Dust SED modelling (with F. Galliano) -- taking consideration of uncertainties
  • Comparing Planck component separation with "blind" component separation techniques. (I.e. PCA, ICA, NMF)